Tool for holding and driving screws



April 5 1966 c. M. M KENZIE TOOL FOR HOLDING AND DRIVING SCREWS INVENTOR. CLARENCE M. McKENZlE ATTORNEY Filed Sept. 14, 1964 United States Patent 3,244,208 TOOL FOR HOLDING AND DRIVING SCREWS Clarence M. McKenzie, Palmyra Road, RD. 1, Canfield, Ohio Filed Sept. 14, 1964, Ser. No. 396,046 Claims. (Cl. 145-52) This invention relates to a rotary tool for holding and driving screws, and more particularly to a tool of the nature in which the head end of a screw is detachably retained in an assembly adapted to be rotated so that the tapered end of the screw may be started into its seat and thereafter be power driven fully into its seat by continued rotation of the tool and inward pressure applied therethrough. The prior art shows a number of tools for accomplishing the same general result but the arrangements heretofore proposed have been both exceedingly complicated and expensive to build as well as being difficult to keep in repair so that these prior devices have not found favor with craftsmen and tradesmen who would ordinarily make extensive use of such equipment. The primary object of the present invention is to so improve a rotary screw holder and driver that the same is exceedingly simple in design, economical to manufacture with high speed automatic equipment, and which is exceedingly easy to use and trouble-free in operation.

While rotary combined screw holders and drivers of the general nature herein involved are capable of a wide variety of uses, they are most advantageous for use in connection with the driving chuck of a portable electric drill and for the purpose of locating and driving home self-tapping sheet-metal screws in the installation of air ducts and outlets, for example. Accordingly, the invention herein will be illustrated and described in such environment although it should be understood that'the meritorious use of the invention is not so limited.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawing wherein there is disclosed a preferred embodiment of the invention.

In the drawing: 1

FIGURE 1 is a side elevation of the tool of the invention as installed in the drive chuck of a conventional portable drill, the view also showing the threaded tip of aself-tapping sheet-metalscrew held in the tool;

FIGURE 2 is a front end view of the tool of FIG- FIGURE 3 is a longitudinal section of the tool of FIGURES land 2 taken along the planes IIIIII of FIGURE 2, and showing the retained screw in longitudinal section; I

FIGURE 4 is a longitudinal section taken along the line IV 1V of FIGURE 2; and 7 FIGURE 5 is a fragmentary section showing the relative position of certain of the component parts when the tool is about to be disengaged from a driven screw. In the drawing, reference numeral 10 designates a tubular shell having an inwardly tapering internal surface 11 at its forward end. The taper 11 terminates at a longitudinal internal surface section 12 in which is slideably received a tubular block 13 (see FIGS. 3-5).

Slideably received in the bore through block 13 is the pointed end 14 of a screwdriver having an integral shank 15 adapted to be rigidly clamped in a conventional chuck 16 of a portable electric drill 17. Near the back end of the shell 10 and slideably received therein is a washer 18 whose aperture receives the shank 15. Interposed between the washer 18 and the block 13 is a coil spring 19 and a pin 20 restricts rearward sliding movement of the washer 18 on the shank 15. It should be obvious that the spring 19 is thus arranged to keep the shank 15 .lC v

normally retracted whereby the pointed end 14 of the screwdriver is retained within the block 13.

The side wall of the block 13 is formed with a longitudinally elongated thru-slot 21 in which is received the projecting end of a pin 22 which is attached to the shank 15 adjacent the pointed end thereof. This limits the rearward movement of the shank 15 relative to the block 13 but nevertheless permits the shank or screwdriver to move forwardly in the block 13 against the action of the spring 19 and to a relative position shown in FIG- URE 5. Block 13 has a longitudinal slot 23 in its outer surface which receives the inner end portion of a retaining screw 24 threaded through the side wall of the shell 10. This slot 23 keeps the longitudinal movement of the block 13 with respect to the shell 10 within a predetermined range while yet permitting the screwhead retaining chuck to be hereinafter described to open up sufficiently to detach the tool from the driven screw.

In the illustrated embodiment of the invention, the

side wall of the block 13 is formed with three circumferentially spaced bores 25 which are drilled inwardly from the front end of the block. Communicating with each of these bores 25 is a bore 26 of much smaller diameter which is drilled into the block 13 from the rear end thereof. Received within each of the bores 26 and extending longitudinally through the connected bore 25 is a length of spring or piano wire 27. It should be noted that those portions of the wires 27 which are received within the bores 26 are effectively restrained against any radial bending whereas the free ends of the wires which are in the larger bores 25 may flex radially inward or outward a substantial extent. It should also be noted from FIGURES 3 and 5. that the small bores 26 are aligned with the wall sections of the larger .bores 25 which are closest to the outer cylindrical surface of the block 13. The free ends of the wires 27 are thus inherently biased to radial outward positions with respect to the longitudinal center axis of the tool. 1 As shown in FIGS. 3-5, the bore through the block 13 is enlarged atits forward end as shown at 28 to a diameter slightly larger than the diameter of the head of the screws .which are intended to be used in the tool. EX- tending radially through the side wall of the block 13 are three bores 29, as shown in FIGURE 4, sli-ght lyless than a complete circle in cross section but substantially greater than a semicircle. The location of these bores 29 coincide vwith the location of the bores 25,-and obviously there-fore the bores 29 intersect the bores 25. Slideably received in each of the bores 29 is a bit 30 having a blind bore therein to receive the free end of the wire 27 which lies in the adjacent bore 25.

Interposed between the rear end of the block 13 and the compression spring 19 is a washer 31' which rides on the shank 1S and .the peripheral portion of which overlies the open ends of the small bores 26. It should now be apparent that the action of the spring 19 prevents the wires 27 from sliding in a rearward direction with respect to the block 13 without any additional fastening. Forward sliding movement of the wires is restrained by the bits 30, these bits in turn being restrained against longitudinal movement with respect to the block 13 by their almost complete circular cross section which snugly fits within the bores 29.

Considering now the operation of the tool above described and assuming first that the tool is empty of the screw to be driven, it will be apparent that if the sleeve 10 is moved rearwardly with respect .to the block 13 (as permitted by the slot 23) the bits 30 will ride out onto the taper 11 of the sleeve and thereby move radially outward by the forces exerted by the wire springs 27. This permits the head of the screw (herein designated by reference numeral 31) to be inserted longitudinally past inner radial ends of the bits 30 into the cavity 28. Now forward movement of the sleeve with respect to the block 13 will draw the bits inwardly into overlying relation with the head of the screw to be driven, as shown in FIG- URE 3, whereby the screw is loaded into and retained in the tool. At this stage the penetrating tip of the screw to be driven may be spotted in relation to the work by manual manipulation of the supporting drill 17. Upon the screw contacting the work, the drill 17 may be urged forwardly to compress the spring 19 and allow the pointed end 14 of the screwdriver shank 15 to slide in the block '13 and into engagement with the slotted or other preformed face of the drive head of the screw. Now upon the application of rotative power to the shank 15, the screw will be driven home. As this takes place and as the forward end of the sleeve engages the work, the bits 30 and consequently the block 13 will, of course, be drawn forwardly with respect to the sleeve and as the bits 30 travel outwardly along the taper 11 they will expand radially to allow the head of the screw to escape past them. The elongation of the slot 21 permits the driving end 14 of the shank 1-5 to project outwardly beyond the bits 30 and the forward end of the sleeve .10 to permit the screw 31 to be fully tightened in its intended location even though its head may then be slightly recessed with respect to any surfiaces encountered by the bits 30 and the forward end of the sleeve 10. As suggested in FIGS. 3 and 5, the bits 30 are slightly radiused to facilitate the above described escape of the screwhead past them.

It should now be apparent that I have provided an improved tool for holding and driving headed screws which is easy to use, simple in design, and economical to pro duce. The component parts are few in number and capable of being made at high speed on automatic equipment. The assembling of the parts is also exceedingly simple, requiring the use of but a single tool to tighten the screw 24.

Since the retaining bits 30 as well as the driver 14, and the sleeve 10 rotate with the screw to be driven there is no need for bearings and wear of the parts is reduced to a minimum. Also, since the tool of the invention is small in size and light in weight, it may readily be employed in the drive chuck of a conventional small electric hand drill.

Having thus described my invention, what I claim is:

1. A tool for holding and driving screws having heads of predetermined maximum diameter and wherein the outer tace of each head has atleast one driving indentation comprising, an elongated bit having one end formed to fit the said indentation while the other end portion thereof is adapted to be fitted into a driving means, a tubular block slideably but non-rotatably fitted on said bit adjacent said formed end and surrounding said formed end, said block having an enlarged bore section extending inwardly from one end thereof to receive the heads of the screws, the side wall of said bore section having circumferentially spaced apertures therein adjacent the said one end of said block, grip bits slideable radially in said apertures and operative when in radially inward positions to engage .the peripheral portions of the inner faces of the heads of the screws, means carried by said :block to yieldingly bias said grip bits to radially outward positions, a sleeve having limited longitudinal sliding fit on said block and having a tapered internal bore section which flares outwardly to the end of the sleeve which is adjacent said grip bits, and spring means housed within said sleeve biasing said elongated bit and block in opposite relative longitudinal directions.

2. A tool according to claim 1 further characterized in that said spring means comprises a spiraled expansion spring slideably received on the first mentioned bit and having one end bearing against an end of said block, a washer on said first mentioned bit and slideably received within said sleeve and against which the other end of said spring is abutted, and pin mean-s limiting sliding movement of said washer on said first mentioned bit in a direction outwardly of said spiraled spring.

3. A tool according to claim 1 wherein said means to yieldingly bias said grip bits comprises a longitudinal thru-bore cfor each of said grip bits and longitudinally aligned therewith, each of said thru-bores being of larger diameter in its end portion adjacent a grip bit than in its other end portion, a length of spring wire received in each of said thru-bores and tightly held in the small diametered portion thereof While being free to flex laterally in the portion of larger diameter, and said wires being connected to said grip bits.

*4. A toolaccording to claim 3 wherein said circumferentially spaced apertures are of such cross section as to retain said grip bits longitudinally with respect to said block, said wires having end portions received in blind bores formed in said grip bits, and means to restrain sliding movement of said wires in said lthru-bores in a longitudinal direction away from said grip bits.

5. A tool according to claim 4 further characterized in that said means to restrain longitudinal sliding movement of said wires in said thru-bores comprises a washer slideable on the first mentioned bit and overlying the adjacent ends of said wires, and an expansion coil spring surrounding said first mentioned bit within said sleeve and having one of its end-s :fixed with respect to said first mentioned bit while its other end abuts against said washer.

References Cited by the Examiner UNITED STATES PATENTS 237,065 1/1881 Stow 52 2,406,952 9/1946 Josepho 145-52, 2,676,506 4/1954 Schultz 8l--125 X 2,840,126 6/1958 Schmitt 145---52 X 3,056,441 10/1962 Helms 145- 52 W ILLIAM FELDMAN, Primary Examiner.

R. V. PARKER, IR., Assistant Examiner. 

1. A TOOL FOR HOLDING AND DRIVING SCREWS HAVING HEADS OF PREDETERMINED MAXIMUM DIAMETER AND WHEREIN THE OUTER FACE OF EACH HEAD HAS AT LEAST ONE DRIVING INDENTATION COMPRISING, AN ELONGATED BIT HAVING ONE END FORMED TO FIT THE SAID INDENTATION WHILE THE OTHER END PORTION THEREOF IS ADAPTED TO BE FITTED INTO A DRIVING MEANS, A TUBULAR BLOCK SLIDEABLY BUT NON-ROTATABLY FITTED ON SAID BIT ADJACENT SAID FORMED END AND SURROUNDING SAID FORMED END, SAID BLOCK HAVING AN ENLARGED BORE SECTION EXTENDING INWARDLY FROM ONE END THEREOF TO RECEIVE THE HEADS OF THE SCREWS, THE SIDE WALL OF SAID BORE SECTION HAVING CIRCUMFERENTIALLY SPACED APERTURES THEREIN ADJACENT THE SAID ONE END OF SAID BLOCK, GRIP BITS SLIDEABLE RADIALLY IN SAID APERTURES AND OPERATIVE WHEN IN RADIALLY INWARD POSITIONS TO ENGAGE THE PERIPHERAL PORTIONS OF THE INNER FACES OF THE HEADS OF THE SCREWS, MEANS CARRIED BY SAID BLOCK TO YIELDINGLY BIAS SAID GRIP BITS TO RADIALLY OUTWARD POSITIONS, A SLEEVE HAVING LIMITED LONGITUDINAL SLIDING FIT ON SAID BLOCK AND HAVING A TAPERED INTERNAL BORE SECTION WHICH FLARES OUTWARDLY TO THE END OF THE SLEEVE WHICH IS ADJACENT SAID GRIP BITS, AND SPRING MEANS HOUSED WITHIN SAID SLEEVE BIASING SAID ELONGATED BIT AND BLOCK IN OPPOSITE RELATIVE LONGITUDINAL DIRECTIONS. 